The present invention relates to the field of assemblies for drawing fuel from a motor vehicle tank.
Numerous devices have already been proposed for drawing fuel from a tank and directing the fuel to feed the engine (carburetor or injector).
Most known devices comprise an electric pump associated with a pressure regulator.
Devices are also known in which the electric pump draws from a reserve, commonly called the xe2x80x9creserve bowlxe2x80x9d placed inside the fuel tank. Such a reserve bowl can be filled from the tank via a float valve which opens to allow fuel to pass from the tank into the reserve bowl whenever the level in the tank is higher than the level in the reserve bowl.
Various configurations have also been proposed comprising a jet pump or Venturi effect pump for feeding the reserve bowl. The jet pump is generally fed by an outlet stage of the main pump or by the outlet of the pressure regulator. It takes fuel in from the tank and its outlet delivers to the reserve bowl.
Document EP-A-0 798 458 describes a pump device designed to be immersed in a motor vehicle tank, said device comprising a main body in which two contiguous cavities are provided, the first cavity having its main opening at the top and containing a pumping sub-assembly, and the second cavity having its main opening on the side and containing a filter cartridge, said cavity being connected to a fixing plate via a duct to the duct of the plate in order to feed fuel to the vehicle, while a pressure regulator is disposed on the side of the cavity having the main opening and is associated with a jet-pump type system which opens out into the first cavity. (page 1, 1.22).
In conclusion, numerous fuel-drawing structures have already been proposed. Nevertheless, most of them are very complex and do not always give satisfaction.
An object of the present invention is to propose novel means for drawing fuel that present performance that is improved compared with known devices.
In one embodiment of the present invention, a fuel-drawing assembly for a motor vehicle tank comprises a main pump (110) associated with a pressure regulator (170) and a reserve bowl (150) fed by a jet pump (160) from which the main pump (110) draws fuel. The jet pump (160) is integrated in an outlet from the pressure regulator (170) to form a subassembly secured to a module (100) comprising the main pump (110) and the reserve bowl (150). A portion of a housing (171) for the pressure regulator (170) is integrated into a wall constituting the reserve bowl (150), and the outlet from the jet pump (160) is associated with means for degassing the fuel before it reaches the reserve bowl (150).
As explained below, the present invention makes it easier to adjust the jet/regulator pump subassembly compared with prior known dispositions.
By integrating these two components it is possible to adjust the pressure regulator in the factory. This adjustment thus makes it possible to take account of the downstream back pressure imposed on the regulator by the jet pump (which downstream back pressure can modify the characteristics of the regulator).
In addition, the structure proposed in the context of the present invention makes it possible to eliminate any need for sealing means to be fitted between the outlet of the pressure regulator and the inlet of the jet pump.
The invention also provides a motor vehicle fuel tank fitted with such a fuel-drawing assembly.